C.8.22.2 Enhanced PET Acquisition Module

Table C.8.22-2 specifies the Attributes that describe PET Acquisitions.

Table C.8.22-2ENHANCED PET ACQUISITION MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Acquisition Start Condition (0018,0073) 1C Description of how the data collection was started. See C.8.22.2.1.1 for Defined Terms. Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Start Density Threshold (0018,9715) 1C The count density that triggered the start of the acquisition, in counts/sec. Required if Acquisition Start Condition (0018,0073) equals DENS.
Start Relative Density Difference Threshold (0018,9716) 1C The relative count density that triggered the start of the acquisition, in counts/sec. Required if Acquisition Start Condition (0018,0073) equals RDD.
Start Cardiac Trigger Count Threshold (0018,9717) 1C The number of cardiac triggers that occurred before starting the acquisition. Required if Acquisition Start Condition (0018,0073) equals CARD_TRIG.
Start Respiratory Trigger Count Threshold (0018,9718) 1C The number of respiratory triggers that occurred before starting the acquisition. Required if AcquisitionStart Condition (0018,0073) equals RESP_TRIG.
Acquisition Termination Condition (0018,0071) 1C Description of how the data collection for the series was stopped. See C.8.22.2.1.2 for Defined Terms. Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Termination Counts Threshold (0018,9719) 1C The count value that triggered the termination of the acquisition. Required if Acquisition Termination Condition (0018,0071) equals CNTS.
Termination Density Threshold (0018,9720) 1C The count density that triggered the termination of the acquisition, in counts/sec. Required if Acquisition Termination Condition (0018,0071) equals DENS.
Termination Relative Density Threshold (0018,9721) 1C The count relative density that triggered the termination of the acquisition, in counts/sec. Required if Acquisition Termination Condition (0018,0071) equals RDD.
Termination Time Threshold (0018,9722) 1C The time duration after which the acquisition was terminated, in sec. Required if Acquisition Termination Condition (0018,0071) equals TIME
Termination Cardiac Trigger Count Threshold (0018,9723) 1C The number of cardiac triggers that triggered the termination of the acquisition. Required if Acquisition Termination Condition (0018,0071) equals CARD_TRIG
Termination Respiratory Trigger Count Threshold (0018,9724) 1C The number of respiratory triggers that triggered the termination of the acquisition. Required if Acquisition Termination Condition (0018,0071) equals RESP_TRIG
Type of Detector Motion (0054,0202) 1C Describes the type of detector motion during acquisition. Defined Terms: STATIONARY = No motion STEP AND SHOOT = Interrupted motion, acquire only while detectors are stationary CONTINUOUS = Gantry motion and acquisition are simultaneous and continuous WOBBLE = wobble motion CLAMSHELL = clamshell motion Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Detector Geometry (0018,9725) 1C Physical arrangement of the detectors in the acquisition system. The radiation entrance surface of a detector may be curved or flat. A curved surface is referred to as cylindrical. Detectors may simultaneously subtend all possible transverse angles from the center of the field of view. Detectors that do not are referred to as partial. Defined Terms: CYLINDRICAL_RING CYL_RING_PARTIAL MULTIPLE_PLANAR MUL_PLAN_PARTIAL Required if Image Type (0008,0008) Value 1 is ORIGINAL and Type of Detector Motion (0054,0202) equals STATIONARY. May be present otherwise, if Image Type (0008,0008) Value 1 is DERIVED and Type of Detector Motion (0054,0202) equals STATIONARY.
Transverse Detector Separation (0018,9726) 1C Distance between opposing detectors, in mm. Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Axial Detector Dimension (0018,9727) 1C Axial detector size in mm. Size of the detector along the table axis. Required if Image Type (0008,0008) Value 1 is ORIGINAL May be present otherwise.
Collimator Type (0018,1181) 1C Collimator Type. Defined Terms: NONE = no collimator RING = transverse septa Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Coincidence Window Width (0054,1210) 1C The width of the coincidence-timing window, in nanoseconds. The maximum time difference between two single events in two opposing detectors that will be accepted as a coincidence event. Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Energy Window Range Sequence (0054,0013) 1C Sequence of Items that describes the energy windows used for this Image. One or more items shall be included in this sequence. See C.8.22.2.1.3 for explanation. Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
>Energy Window Lower Limit (0054,0014) 1 The lower limit of the energy window, in KeV.
>Energy Window Upper Limit (0054,0015) 1 The upper limit of the energy window, in KeV.
Table Motion (0018,1134) 1 Enumerated Values: STATIC = Table is stationary during data acquisition. DYNAMIC = Table is moving during data acquisition.
Time of Flight Information Used (0018,9755) 1 Specifies whether or not Time-of-Flight information was used in creation of the image. Enumerated Values: TRUE FALSE
View Code Sequence (0054,0220) 1 Sequence that describes the projection of the anatomic region of interest. Only a single Item shall be included in this sequence.
>Include ‘Code Sequence Macro’ Table 8.8-1 Baseline CID 26.
>View Modifier Code Sequence (0054,0222) 2C View Modifier. Required if needed to fully specify the View. Zero or one item shall be included in this sequence.
>>Include ‘Code Sequence Macro’ Table 8.8-1 Baseline CID 23.
Slice Progression Direction (0054,0500) 1C Describes the anatomical direction that a set of slices, identified by the same Stack ID (0020,9056), are progressing, as the slices are considered in order by In Stack Position Number (0020,9057). Meaningful only for cardiac images. Enumerated are: APEX_TO_BASE BASE_TO_APEX ANT_TO_INF = Anterior to Inferior INF_TO_ANT = Inferior to Anterior SEPTUM_TO_ WALL = Septum to Lateral Wall WALL_TO_SEPTUM = Lateral Wall to Septum Required if View Code Sequence (0054,0220) equals (G-A186, SRT,”Short Axis”). May be present otherwise.

C.8.22.2.1 Enhanced PET Acquisition Module Attribute Descriptions

C.8.22.2.1.1 Acquisition Start Condition

Acquisition Start Condition (0018,0073) is the method of starting acquisition data collection. The Defined Terms and definitions are:

DENS = preset count density (counts/sec) was reached

RDD = preset relative count density difference (change in counts/sec) was reached

MANU = acquisition was started manually

AUTO = start automatically, when ready

CARD_TRIG = preset number of cardiac triggers was reached

RESP_TRIG = preset number of respiratory triggers was reached.

C.8.22.2.1.2 Acquisition Termination Condition

Acquisition Termination Condition (0018,0071) is the method of acquisition termination which has actually applied to the data collection. The Defined Terms and definitions are:

CNTS = preset counts was reached.

DENS = preset count density (counts/sec) was reached

RDD = preset relative count density difference (change in counts/sec) was reached

MANU = acquisition was terminated manually

OVFL = data overflow occurred.

TIME = preset time limit was reached

CARD_TRIG = preset number of cardiac triggers was reached

RESP_TRIG = preset number of respiratory triggers was reached

C.8.22.2.1.3 Energy Window Range Sequence

Multiple energy windows are allowed in order to allow coincidence events based on additional Energy Windows (e.g. Compton events scattered in the detector). All energy windows are assumed to contribute to all frames in this image.